Chamfering device



Sept. 12, 1944. 1 MOODY 2,358,241

CHAMFERING DEVICE Filed March 10, 1943 3 Sheets-Sheet 2 maz zz'n yoodg,

IN V EN TOR.

A'ITD R N EYS Sept. 12, 1944. J. M. MOODY 2,358,241

' CHAMFERING DEVqTCE Filed March 10, 1943 3 Sheets-Sheet 3 45 T i 1 14/Q Jlfariinjyggg A'ITEIR NEYS Patented Sept. 12, 1944 UNITED STATESPATENT OFFICE CHAMFERING DEVICE J. Martin Moody, Arlington, Va.Application March 10, 1943, Serial No. 478,715 A '1 Claim.

My invention relates to the grinding of taps and similar tools, and hasamong its objects and advantages the provision of an improved chamferingtool designed to facilitate such operations.

In the accompanying drawings:

Figure 1 is a side view of the invention.

Figure 2 is a view of the opposite side.

Figure 3 is an end view.

Figure 4 is a partial sectional view of the opposite end of the tool. 4Figure 5 is an enlarged sectional view of agrinding feed cam mechanism.

Figure 6 is a'view of a part of the structure of Figure 5 illustratingthe manner in which the cam operation may be modifiedto suit the needsof different types of tools.

Figure 7 is a top view of the toolillustrating its association with agrinder.

Figure 8 is an enlarged sectional view along the line 8-8 of Figure 7.

Figure 9 is a view illustrating a pin type centering device for the tap.

Figure 10 illustrates a socket type centering device for the tap, and

Figure 11 illustrates an end view of a tap showing the manner in whichthe chamfer is cut. 4 In the embodiment of the invention selected forillustration, I make use of a base l2 which may be attached to asupport[4. The base is provided with an upstanding wall or bracket l6, whichmay be made in one piece with the base. A tool support I8 is mounted onthe base. This support includes a web having projections 22 lyingadjacent end faces 24 on a body 26 formed integrally with the base l2adjacent the bracket l6. Screws 28 are threaded through the projections22 and are provided with tapered ends receivable in correspondinglytapered recesses 30 in the end faces 24 to pivotally connect the toolmount IS with the base 10/ v In Figure 4, the bracket I6 is providedwith an opening 32 for loosely receiving a screw 34 threaded into thetool mount l8. A compression spring 36 is mounted on the screw 34 and isinterposed between the bracket l6 and the screw head 38 to yieldinglyhold the tool mount against the bracket 16.

Referring to Figures 7 and 8, the tool mount 18 includes a cylindricalbody 40 provided with a bore 42 in which is rotatably mounted a sleeve44 provided with a head 46 having internal threads 46 for connectionwith threads 50 on a spindle 52 rotatably mounted in the sleeve 44.

A chuck member 54 is internally threaded at 56 for connection withexternal threads 58 on the head 46, which chuck member may be ofconventional design with respect to its tapered face 66 and the coactingdogs 62 to be clamped on the v 10 to provide a depression for theabutting end of the spindle 52.

A knob 12 is fixed to the'spindle 52 to facilitate rotation thereof.While the sleeve 44 is mounted for rotation in the bore 42 andthespindle 52 may be rotated relatively to the sleeve, the sleeve andthe spindle are fixedly related when the chuck member 54 is turned tothe position of'Figure 8, which frictionally locks all the parts so thatrotation of the spindle 52 will also cause rotation of the sleeve 44 toimpart rotary motion to the tap 60, as when the tap is being chamferedby a grinding stone 14 in Figure 7.

The tap 66 is conventional and includes the usual flutes 16 whichdivides the circumferential face'of the tap longitudinally toprovide'ribs 18, these ribs being provided with the usual cut threads 80and chamfered or ground threads 82. The present invention is concernedwith chamfering the threads 82. Figure 11 illustrates an end view of thetap 66, the tap having four ribs 18. The tap is rotated counterclockwiseand the chamfered faces of the tap are progressively deepened from theirleading edges 84 to the trailing edges 86.- My tool operates to advancethe tap 66 against the stone 14 as the chamfer is being cut from theleading edge 84 to the trailing edge 86.

The means for advancing the tap 66 comprises a cam mechanism 88, bestillustrated in Figures 3, 5, '7 and 8. In Figure 8 a flange 90 isfixedly related to the sleeve 44, which flange includes a hub 92 fixedto the sleeve 44 by a set screw'94.

This hub abuts one end of the body 46, while the head 46 abuts the otherend of the cylindrical body to restrain the sleeve 44 from relativeaxial movement.

The flange is spaced sufiiciently far from the cylindrical body 46 toprovide accommodation for four rollers 96 rotatably mounted on pins 98fixed to the flange 90. These rollers are spaced 90 degrees apart andare of a common diameter. A cam arm I00 is pivoted intermediate its endsat I02 to one end of the bracket 16. This cam arm lies in the plane ofthe cam rollers 96.

In Figure 5, the cam arm I00 is provided with a cam face H14 arrangedfor contact with the cam rollers 96 through rotation of the flange 90.This flange is rotated clockwise when viewing Figure 3, butcounterclockwise in Figure 5. With the cam rollers 96 positionedaccording to Figure 5, two cam rollers lie in engagement with the camarm I00, and one cam roller 96 lies in engagement with the face I04 toshift the flange 90 and its cam rollers 96 to the left through rotationof the flange. Such lateral shifting of the flange imparts pivotalmovement to the tool mount I8 to advance the tap 66 against the grindingstone I4.

A compression spring I06 is mounted on a screw I08 extending looselythrough a lug IIO fixed to the bracket I6 and is threaded through a lipI I2 attached to the lower end of the cam arm I00. While the screw I08is loosely mounted in the lug IIO, the screw restrains the arm I fromclockwise rotation, when viewing Figure 5.

To support such a tap, the head I22 is provided with a tapered socket orrecess I28 for receiving the tapered end I30 on a tap I32. The arm I20is removably mounted on a pin I34 at one end of the shaft H6, and thearm is made secure against accidental displacement by a set screw I36.Thus the arm I20 may be reversed to present either the pin I24 or therecess I28 to the tap being ground. A set screw I38 is threaded in theweb 20 to fixedly secure the shaft II6. This shaft, however, may beadjusted to different positions to accommodate taps of different Tochamfer the top 66, the cam mechanism 88 r is first adjusted to theposition of Figure 5, which position is easily determined by-the senseof touch, since two cam rollers 96 engage the cam arm. The tap 66 isthen made secure in the chuck in the position of Figure 7. The positionof the tap with respect to rotation about its longitudinal axis isdetermined by bringingthe tap to a position where one of the flutesI6'faces directly upwardly, as shown in Figure '7. The chuck member 54and the tap 66. are then held against rotation and rotation is impartedto the spindle 54 to'fixedly relate the parts.

With the parts fixedly related, the tap 66 may 7 be rotated relativelyto the grinding stone 14. Since the cam rollers 96 are the same innumber as the ribs 18, each rib will be cut progressively deeper fromits leading edge to its trailing edge, since the tap is set in apredetermined position with respect to the cam rollers and the cam armI00. The cam arm is restrained from pivotal movement by the screw I08,and the spring I06 imparts sufiicient pressure to restrain the screwfrom accidental rotation. The oscillatory movement'of the tool mount 88may be'varied through adjustment of the cam 'arm I00 by the screw I08.

To facilitate precise positioning of the tap 66 in the tool mount, analigning device H4 is employed. This device comprises a shaft 6adjustably mounted in a bore H8 in the web 20 and paralleling the axis"of the spindle 52. To one end of' the shaft H6 is fixed a' rightangular arm I20 provided with a head I22. This head is provided with atapered centering pin I24 for re, ception in a tapered recess I26 in theend of the tap 66. The recess I26 lies at the axial center of the tap,and the pin I24 has its axis paralleling the axis of the spindle 52 andis coaxial therewith. Thus the pin I24 may be brought snugly within therecess 26 and supported therein while the tap 66 is being clamped in thechuck.

Some taps are provided with pointed ends.

lengths. After placement of the tap in the chuck, the. shaft H6 isadjusted to bring its pin or socket aligning meansinto engagement withthe end of the tap. The shaft is then retracted to exert pressure on theend of the tap, after which the set screw I38 is tightened.

Figures 5and 6 illustrate the flange as being provided with extra pins98. These pins are so spaced as to accommodate difierent arrangements ofthe cam rollers 96. Figure 5 illustrates four cam rollers 96, whileFigure 6 illustrates three cam rollers I42. These camrollers are spaceddegrees apart for service in connection with a tool having three ribs tobe ground. In servicing a six-ribbed tool, additional cam rollers I44may be mounted on the flange. An oil cup I46 is'mounted on thecylindrical body 40 to supply oil to a bore I48 leading to the sleeve44.

The support I4 is provided with an upstanding pin I46 receivable in abore I48 in the base I2. The base may be fixed against rotation by a setscrew I50 threaded in the base for connection with the pin I46.

Without further elaboration, the foregoing will so fully explain byinvention, that others may, by applying current knowledge, readily adaptthe same for use under various conditions of service.

I claim:

In grinding mechanism of the character described, a support, a bodypivotally mounted on the support and spring biased to a retractedposition thereon, a spindle rotatably extended through the body having atool carrying chuck at one end,.said spindle having its axis parallelwith the pivot axis of the body, a flange disposed circumferentiallyabout and mounted to turn with the spindle, a plurality of pins fixed incircumferentially spaced relation to and extending axially from one faceof the flange, said pins being disposed on a circle concentric with theaxis of the. spindle, a roller rotatably mounted on each pin, and a cammember mounted on the support in position to engage the circumference ofthe respective rollers to effect transverse movement of the spindleduring rotation thereof.

J. MARTIN MOODY.

